Immunomodulatory mechanisms of mesenchymal stromal cells for the treatment of GVHD

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Heather Melichar, Ph.D.

Heather Melichar is a researcher at the Maisonneuve-Rosemont Hospital Research Center and an Assistant Professor in the Department of Medicine at the Université de Montréal. After completing a PhD studying lineage fate decisions during T cell development in the lab of Dr. Joonsoo Kang at the University of Massachusetts Medical School, Dr. Melichar performed a post-doctoral fellowship at the University of California, Berkeley, with Dr. Ellen Robey where she developed platforms to study T cell development in situ. Dr. Melichar established her independent research group in Montreal in January 2014, where her lab studies the cellular and molecular mechanisms that regulate T cell development and function. Recently, Dr. Melichar was presented with FRQS Chercheurs-boursiers and CIHR New Investigator awards. Dr. Melichar’s lab is the recipient of generous transition funding from the Cole Foundation, the Maisonneuve-Rosemont Hospital Foundation, and the Université de Montréal, which supported early studies that led to successful project grants from the SickKids Foundation, CIHR, and Canadian Cancer Society.

Support from the Cole Foundation is being used in the Melichar lab to expand upon the identification and characterization of immunomodulatory molecules regulating T cell activation and function. In particular, Dr. Melichar’s group has uncovered a role for a new immunoregulatory molecule found at high levels on some mesenchymal stromal cell (MSCs) preparations that interferes with T cell function. MSCs are known to suppress T cell function and are being used with some success to treat graft-versus-host-disease, an unfortunate, and often severe, complication of bone marrow transplants in pediatric leukemia patients that have relapsed, or are at high risk of relapse, after initial treatment. However, several aspects of T cell suppression by MSCs are not clear. Therefore, defining the molecules that MSCs use to trigger T cell suppression could enable the development of more effective, targeted therapeutic strategies. Dr. Melichar’s group is characterizing the interaction of this inhibitory molecule with proteins found on human immune cells to better understand how such interactions enable MSCs to inhibit immune cell function.